xpcom/ds/nsISimpleEnumerator.idl

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  37
  38 #include "nsISupports.idl"
  39
  40 /**
  41  * Used to enumerate over elements defined by its implementor.
  42  * Although hasMoreElements() can be called independently of getNext(),
  43  * getNext() must be pre-ceeded by a call to hasMoreElements(). There is
  44  * no way to "reset" an enumerator, once you obtain one.
  45  *
  46  * @status FROZEN
  47  * @version 1.0
  48  */
  49
  50 [scriptable, uuid(D1899240-F9D2-11D2-BDD6-000064657374)]
  51 interface nsISimpleEnumerator : nsISupports {
  52   /**
  53    * Called to determine whether or not the enumerator has
  54    * any elements that can be returned via getNext(). This method
  55    * is generally used to determine whether or not to initiate or
  56    * continue iteration over the enumerator, though it can be
  57    * called without subsequent getNext() calls. Does not affect
  58    * internal state of enumerator.
  59    *
  60    * @see getNext()
  61    * @return PR_TRUE if there are remaining elements in the enumerator.
  62    *         PR_FALSE if there are no more elements in the enumerator.
  63    */
  64   boolean hasMoreElements();
  65
  66   /**
  67    * Called to retrieve the next element in the enumerator. The "next"
  68    * element is the first element upon the first call. Must be
  69    * pre-ceeded by a call to hasMoreElements() which returns PR_TRUE.
  70    * This method is generally called within a loop to iterate over
  71    * the elements in the enumerator.
  72    *
  73    * @see hasMoreElements()
  74    * @return NS_OK if the call succeeded in returning a non-null
  75    *               value through the out parameter.
  76    *         NS_ERROR_FAILURE if there are no more elements
  77    *                          to enumerate.
  78    * @return the next element in the enumeration.
  79    */
  80   nsISupports getNext();
  81 };